U.S. patent application number 16/854238 was filed with the patent office on 2020-11-05 for pipe joint seal for polymer piping.
This patent application is currently assigned to Press-Seal Corporation. The applicant listed for this patent is Press-Seal Corporation. Invention is credited to Jimmy D. Gamble, Jacob L. B. Morris, Peter J. Skinner.
Application Number | 20200347966 16/854238 |
Document ID | / |
Family ID | 1000004823336 |
Filed Date | 2020-11-05 |
United States Patent
Application |
20200347966 |
Kind Code |
A1 |
Skinner; Peter J. ; et
al. |
November 5, 2020 |
PIPE JOINT SEAL FOR POLYMER PIPING
Abstract
A seal assembly is configured for use at PVCO pipe junctions.
The seal assembly includes a main seal body made of a monolithic
resilient material, such as rubber, and a stiffener. The seal has a
stiffener pocket sized and configured to accept the stiffener, such
that the stiffener can be assembled to the seal body by hand. This
assembly can then be installed into the bell end of a first PVCO
pipe, and a spigot end of a second PVCO pipe may then be inserted
into the bell end and engaged with a main sealing lobe of the seal
assembly. The seal assembly is configured to reliably withstand the
insertion process, without damage or degradation to the sealing
structures. Once installed, the seal assembly provides a robust
fluid-tight seal along all potential leak paths between the seal
assembly and the first and second pipes.
Inventors: |
Skinner; Peter J.; (Columbia
City, IN) ; Gamble; Jimmy D.; (Kendallville, IN)
; Morris; Jacob L. B.; (Huntington, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Press-Seal Corporation |
Fort Wayne |
IN |
US |
|
|
Assignee: |
Press-Seal Corporation
Fort Wayne
IN
|
Family ID: |
1000004823336 |
Appl. No.: |
16/854238 |
Filed: |
April 21, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62842045 |
May 2, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16L 17/025 20130101;
F16L 21/035 20130101 |
International
Class: |
F16L 17/025 20060101
F16L017/025; F16L 21/035 20060101 F16L021/035 |
Claims
1. A seal assembly for a polymer pipe joint, the seal assembly
comprising: an annular flexible seal body configured to be
installed about an inner periphery of the polymer pipe joint, such
that the seal body defines a flow path therethrough with a flow
axis, the seal body comprising: a spigot-side sealing surface; a
bell-side sealing surface angled with respect to the spigot-side
sealing surface, both the spigot-side sealing surface and the
bell-side sealing surface facing radially outwardly from the flow
axis; a main sealing lobe extending radially inwardly from the seal
body; and a stiffener pocket extending into the seal body from the
bell-side sealing surface; and an annular stiffener sized to be
received within and occupy the stiffener pocket.
2. The seal assembly of claim 1, wherein the seal body further
comprises a nose at a spigot-side end of the seal body.
3. The seal assembly of claim 2, wherein a radial inward surface
extending away from the nose includes a concavity.
4. The seal assembly of claim 1, wherein the seal body further
comprises a locking fin at a bell-end side of the seal body, the
locking fin extending radially inwardly from the seal body by an
amount less than the radial inward extend of the main sealing
lobe.
5. The seal assembly of claim 4, wherein the main sealing lobe is
sized to deflect and deform into contact with the rest of the seal
body but without contacting the locking fin.
6. The seal assembly of claim 1, wherein the annular stiffener
comprises: a central portion; a spigot-end portion extending
radially inwardly away from the central portion; and a bell-end
portion extending radially outward away from the central
portion.
7. The seal assembly of claim 6, wherein the stiffener pocket has a
shape and size commensurate with the shape and size of the annular
stiffener, such that the annular stiffener occupies the entirety of
the stiffener pocket.
8. The seal assembly of claim 1, wherein the bell-side sealing
surface comprises a first sealing surface and a second sealing
surface on opposite sides of the stiffener.
9. The seal assembly of claim 1, wherein the seal body has a
substantially constant durometer throughout its cross-sectional
area.
10. The seal assembly of claim 1, wherein a durometer of the seal
body is between 55 and 70 as measured on the shore A scale.
11. The seal assembly of claim 1, wherein the stiffener is
mechanically bonded to the seal body, without the use of adhesive
or other chemical bonding.
12. The seal assembly of claim 1, in combination with a first
polymer pipe having a bell end including a groove having the seal
assembly received therein, the bell end having a first radial
extent upstream and downstream of the groove, and the groove have a
second radial extent larger than the first radial extent, the seal
body received within the groove and the main sealing lobe extending
radially inward of the first radial extent.
13. The seal assembly of claim 12, wherein the seal body further
comprises a nose at a spigot-side terminus of the seal body, the
nose radially outside of the first radial extent.
14. The seal assembly of claim 13, further comprising a second
polymer pipe having a spigot end received within the bell end of
the first polymer pipe, the spigot end deforming and deflecting the
main sealing lobe toward the seal body.
15. The seal assembly of claim 12, wherein the stiffener abuts an
adjacent surface of the groove.
16. The seal assembly of claim 15, wherein the bell-side sealing
surface comprises a first sealing surface and a second sealing
surface on opposite sides of the stiffener and engaged with the
adjacent surface of the groove, such that the stiffener pocket is
sealed from the flow path.
17. A polymer pipe joint comprising: a seal assembly comprising: an
annular flexible seal body configured to be installed about an
inner periphery of the polymer pipe joint, such that the seal body
defines a flow path therethrough with a flow axis, the seal body
comprising: a spigot-side sealing surface; a bell-side sealing
surface angled with respect to the spigot-side sealing surface,
both the spigot-side sealing surface and the bell-side sealing
surface facing radially outwardly from the flow axis; and a main
sealing lobe extending radially inwardly from the seal body; and a
nose at a spigot-side terminus of the seal body; and a first
polymer pipe having a bell end including a groove having the seal
assembly received therein, the bell end having a first radial
extent upstream and downstream of the groove, and the groove have a
second radial extent larger than the first radial extent, the seal
body received within the groove and the main sealing lobe extending
radially inward of the first radial extent, wherein the nose of the
seal body is radially outside of the first radial extent.
18. The polymer pipe joint of claim 17, wherein the nose defines a
distance from the first radial extent of the first polymer pipe
that is at least 50% of a minimum thickness of the seal body.
19. A method of configuring a seal assembly for use in sealing a
bell of a first pipe and a spigot end of a second pipe comprising:
providing a sealing body assembly including a spigot-side sealing
surface, a bell-side sealing surface, a main sealing lobe, and a
stiffener pocket; providing two or more annular stiffeners wherein
each stiffener has a different size of an annular diameter;
selecting one of the one or more annular stiffeners based on an
annular diameter of the bell and an annular diameter of the spigot;
inserting the selected annular stiffener into the stiffener pocket
of the sealing body; and determining if a seal between the
bell-side sealing surface, the spigot-side sealing surface, and the
lobe is water tight after inserting the selected annular stiffener
into the stiffening pocket.
20. The method of claim 19, further comprising: determining that
the seal between the bell-side sealing surface, the spigot-side
sealing surface, and the lobe is not water tight after inserting
the selected annular stiffener; removing the first annular
stiffener from the stiffener pocket; selecting a second annular
stiffener from the one or more annular stiffeners based on the
annular diameter of the bell and the annular diameter of the
spigot; inserting the selected second annular stiffener into the
stiffener pocket of the sealing body; determining that the seal
between the bell-side sealing surface, the spigot-side sealing
surface, and the lobe is water tight after inserting the selected
second annular stiffener into the stiffening pocket.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Patent Application Ser. No. 62/842,045,
filed on May 2, 2019, the entire disclosure of which is expressly
incorporated by reference herein.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to seals used at pipe joints
and, in particular, to seals used in connection with Molecularly
Oriented Polyvinyl Chloride (PVCO) pipes.
2. Description of the Related Art
[0003] PVCO piping, which is made from molecularly oriented
polyvinyl chloride, can be used for conveyance of liquids or other
flowable material. In particular, PVCO piping is gaining increased
acceptance for use in municipal underground systems, such as sewage
and wastewater and potable water conveyance.
[0004] PVCO pipes are made by "stretching" warm PVC to increase the
inner diameter thereof. This "stretching" is accomplished by
passing a PVC pipe over a set of progressively larger mandrels.
This sets the molecules in a strong orientation to create PVCO
piping, which is suitable for use in high-strength applications
such as underground sewage, water and other conveyance systems.
[0005] Existing flexible seals or gaskets for sealing PVCO pipes
are known. At a connection between the bell end of a first pipe and
the spigot end of a second pipe, the spigot end is inserted into
the bell end. The bell end includes a flexible seal which is
deformed or deflected by the spigot end in an attempt to form a
fluid-tight seal. This flexible seal is typically installed into a
groove formed in the sidewall of the pipe, and includes a seal lobe
which, when undeformed, occupies part of the cross-sectional area
normally occupied by the spigot end. When the spigot end is
inserted into the bell end, this seal lobe deformed or deflected to
create the seal. However, known seal designs may be prone to
"rolling out" of the groove when engaged by the spigot end, which
represents a complete failure of the seal.
[0006] What is needed is an improvement over the foregoing.
SUMMARY
[0007] The present disclosure provides a seal assembly configured
for use at PVCO pipe junctions. The seal assembly includes a main
seal body made of a monolithic resilient material, such as rubber,
and a stiffener. The seal has a stiffener pocket sized and
configured to accept the stiffener, such that the stiffener can be
assembled to the seal body by hand. This assembly can then be
installed into the bell end of a first PVCO pipe, and a spigot end
of a second PVCO pipe may then be inserted into the bell end and
engaged with a main sealing lobe of the seal assembly. The seal
assembly is configured to reliably withstand the insertion process,
without damage or degradation to the sealing structures. Once
installed, the seal assembly provides a robust fluid-tight seal
along all potential leak paths between the seal assembly and the
first and second pipes.
[0008] In one form thereof, the present disclosure provides a seal
assembly for a polymer pipe joint, the seal assembly including an
annular flexible seal body configured to be installed about the
inner periphery of the polymer pipe joint, such that the seal body
defines a flow path therethrough with a flow axis, and an annular
stiffener. The seal body includes a spigot-side sealing surface; a
bell-side sealing surface angled with respect to the spigot-side
sealing surface, both the spigot-side sealing surface and the
bell-side sealing surface facing radially outwardly from the flow
axis; a main sealing lobe extending radially inwardly from the seal
body; and a stiffener pocket extending into the seal body from the
bell-side sealing surface. The annular stiffener is sized to be
received within and occupy the stiffener pocket.
[0009] In another form thereof, the present disclosure provides a
polymer pipe joint including a seal assembly including an annular
flexible seal body configured to be installed about an inner
periphery of the polymer pipe joint, such that the seal body
defines a flow path therethrough with a flow axis, the seal body
including a spigot-side sealing surface; a bell-side sealing
surface angled with respect to the spigot-side sealing surface,
both the spigot-side sealing surface and the bell-side sealing
surface facing radially outwardly from the flow axis; and a main
sealing lobe extending radially inwardly from the seal body; and a
nose at a spigot-side terminus of the seal body; and a first
polymer pipe having a bell end including a groove having the seal
assembly received therein, the bell end having a first radial
extent upstream and downstream of the groove, and the groove have a
second radial extent larger than the first radial extent, the seal
body received within the groove and the main sealing lobe extending
radially inward of the first radial extent, wherein the nose of the
seal body is radially outside of the first radial extent.
[0010] In a further form thereof, the present disclosure provides a
method of configuring a seal assembly for use in sealing a bell of
a first pipe and a spigot end of a second pipe comprising:
providing a sealing body assembly including a spigot-side sealing
surface, a bell-side sealing surface, a main sealing lobe, and a
stiffener pocket; providing two or more annular stiffeners wherein
each stiffener has a different size of an annular diameter;
selecting one of the one or more annular stiffeners based on an
annular diameter of the bell and an annular diameter of the spigot;
inserting the selected annular stiffener into the stiffener pocket
of the sealing body; and determining if a seal between the
bell-side sealing surface, the spigot-side sealing surface, and the
lobe is water tight after inserting the selected annular stiffener
into the stiffening pocket.
[0011] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention as
claimed. Other embodiments will be apparent to those skilled in the
art from consideration of the specification and practice of the
invention disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above mentioned and other features and objects of this
invention, and the manner of attaining them, will become more
apparent and the invention itself will be better understood by
reference to the following description of embodiments of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0013] FIG. 1 is a perspective view of a seal assembly made in
accordance with the present disclosure, shown along an installation
path into a bell end of a pipe;
[0014] FIG. 2 is a perspective, cross-section view of the seal
assembly shown in FIG. 1, after installation into the bell end of
the first pipe, and showing a second pipe in the beginning stages
of assembly to the first pipe;
[0015] FIG. 3 is an elevation, cross-section view of the seal
assembly installed in the bell end of a pipe, as shown in FIG.
2;
[0016] FIG. 4 is an elevation, cross-section view of the seal
assembly shown in FIGS. 1 and 2;
[0017] FIG. 5 is an elevation, exploded, cross-section view of the
seal assembly of FIG. 4;
[0018] FIG. 6 is an elevation, cross-section view of the pipe
assembly of FIG. 2, in which a spigot end of a pipe is approaching
but not yet in contact with the seal assembly;
[0019] FIG. 7 is another elevation, cross-section view of the pipe
assembly of FIG. 6, in which the spigot end of the pipe is
initiating contact with a main sealing lobe of the seal
assembly;
[0020] FIG. 8 is another elevation, cross-section view of the pipe
assembly of FIG. 6, in which the spigot end is fully engaged with
the seal assembly; and
[0021] FIG. 9 is another elevation, cross-section view of the pipe
assembly of FIG. 8, illustrating a resistance to removal of the
spigot end by the seal assembly.
[0022] FIG. 10 is an elevation, cross-section view of the seal
assembly of FIG. 8, illustrating variations in the diameter of the
stiffener within the seal assembly.
[0023] Corresponding reference characters indicate corresponding
parts throughout the several views. Although the exemplifications
set out herein illustrate embodiments of the invention, in several
forms, the embodiments disclosed below are not intended to be
exhaustive or to be construed as limiting the scope of the
invention to the precise forms disclosed.
DETAILED DESCRIPTION
[0024] The present disclosure is directed to a seal assembly 20,
shown in FIGS. 1-10, which is designed to be user-installed into a
groove 15 formed in a bell end 14 of a first pipe 12 (FIG. 1). As
described in detail below, the seal assembly 20 provides an
effective, reliable and durable fluid-tight seal between pipes 12
and 16, in part by including features which withstand the forces
exerted on seal assembly 20 during coupling of bell end 14 to a
spigot end 18 of a second PVCO pipe 16 (FIGS. 2 and 6-8).
[0025] As best seen in FIG. 2, bell end 14 has an expanded diameter
compared to the main body of pipe 12, such that bell end 14 can
accept the spigot end 18 of a second pipe 16. In a typical
installation, pipes 12, 16 are identical, such that each pipe
includes a bell end and a spigot end. Within bell end 14, the
expanded portion includes a first radial extent upstream and
downstream of groove 15, and groove 15 has a second radial extent
larger than the first radial extent, thereby providing a space
sized to receive seal assembly 20. The radial extent of the rest of
pipe 12 is the flow path along a longitudinal flow axis A (FIG. 1),
and the diameter of this flow path establishes the nominal diameter
of pipe assembly 10. For purposes of the present disclosure, an
"axial" direction is a direction along or parallel to axis A, while
a "radial" direction is perpendicular to axis A. An "inner" or
"radially inward" feature is one relatively closer to or facing
toward axis A, while an "outer" or "radially outward" feature is
relatively further from or facing away from axis A.
[0026] As best seen in FIGS. 4 and 5, seal assembly 20 is a two
piece, interlocking design including a seal body 22 and stiffener
24. Seal body 22 and stiffener 24 are annular structures, as shown
in FIG. 1. Seal body 22 is made of a flexible material such as
rubber and has a constant density and durometer throughout the
cross-sectional area of seal body 22. Stiffener 24 is sized and
configured to be received within stiffener pocket 32 of seal body
22, as shown in FIG. 5 and further described below, and is made
from a material more rigid than seal body 22 to provide mechanical
support and distribution of forces throughout the seal body 22 in
use. Stiffener 24 and seal body 22 are designed to be flexible
enough stiffener 24 to be installed by hand into pocket 32 of seal
body 22, and for the assembly 20 to then be installed by hand into
groove 15 of bell end 14 of a pipe 12 (FIG. 1).
[0027] In an exemplary embodiment, seal body 22 may be made from
SBR, EPDM, TPE or any other suitable resilient material, and has a
shore A durometer between 50 and 65. Stiffener 24 may be made from
any of various different grades of engineered thermoplastic resins
such PP, HDPE, or PE, and may include various types of different
fillers or additives as needed to achieve desired performance
characteristics. Stiffener 24 may have a shore D durometer of
between 65 and 90. These materials and material properties allow
the shape and configuration of pocket 32 of main seal body 22 to
resiliently deform to accept the insertion of stiffener 24, and the
resulting seal assembly 20 remains flexible enough to be
resiliently deformed as is worked into place within groove 15 of
bell end 14 of pipe 12 (FIG. 2).
[0028] Turning to FIG. 3, seal assembly 20 is shown installed
within groove 15, which includes inwardly-facing sloped surfaces
which are approximately perpendicular to one another, and with a
rounded transition between these surfaces. As illustrated, a
spigot-side groove sealing surface 26 engages one of these sloped
surfaces within groove 15, while a pair of bell-side groove sealing
surfaces 28, 29 engage the opposing sloped surface of groove 15.
Spigot-side surface 26 and bell-side surfaces 28, 29 are angled
with respect to one another and have a rounded transition
corresponding to the geometry of the inner surfaces of groove 15,
such that the radially outwardly-facing sealing surfaces 26, 28 and
29 collectively conform to groove 15 as shown. This conformity, in
conjunction with the action of stiffener 24 and the other features
of sealing body 20 described in detail below, ensures a fluid-tight
fit between the radially outwardly-facing surfaces 26, 28 and 29 of
seal body 22 and the abutting radially inwardly facing surfaces of
groove 15.
[0029] As best seen in FIG. 5, stiffener pocket 32 interrupts the
bell-side sealing surface of seal body 22, such that the first and
second sealing surfaces 28, 29 are on opposite sides of stiffener
pocket 32 and, therefore, on opposite sides of stiffener 24 after
installation (FIG. 4). This arrangement provides a fluid-tight seal
for stiffener pocket 32 from both the spigot-side and the bell-end
side, as best shown in FIG. 3, while also permitting stiffener 24
to come in direct contact with the inwardly facing surface of
groove 15 to provide robust mechanical support to seal body 22 as
further described below. Moreover, this mechanical support
cooperates with the conformity of sealing surfaces 26, 28 and 29 to
the surface of groove 15 to ensure that both fluid egress from the
flow path defined by pipe assembly 10 (FIG. 2), as well as fluid
ingress into this flow path, are both protected against by seal
assembly 20.
[0030] Stiffener pocket 32 has a shape and size commensurate with
the shape and size of the stiffener 24, such that stiffener 24
occupies the entire volume of stiffener pocket 32 when installed to
seal body 22 (FIG. 4). In particular and referring to FIG. 5,
stiffener 24 has a three-part profile including a central portion
24A, spigot end portion 24B and bell-end portion 24C. Central
portion 24A defines axis AC extending along a generally axial
direction (i.e., parallel to axis A), while spigot end portion 24B
extends radially inwardly from central portion 24A along axis AS to
form angle .beta. of between 20 and 30 degrees, such as about 25
degrees or, in the illustrated embodiment, 24 degrees. The opposing
bell-end portion 24C extends radially outwardly from central
portion 24A along axis AB, forming angle .gamma. which is larger
than angle .beta., and equal to between 30 and 50 degrees, such as
about 40 degrees or, in the illustrated embodiment, 42 degrees. As
noted above, stiffener pocket 32 is formed to have the same size
and shape as stiffener 24 in cross-section, such that stiffener
pocket 32 also defines axes AC, AS and AB and angles .beta. and
.gamma..
[0031] As best seen in FIG. 4, this spatial arrangement for
stiffener 24 and stiffener pocket 32 establishes a relatively
constant material thickness for seal body 22, such that a minimum
nominal thickness of seal body 22 is maintained throughout its
cross-sectional extent. In particular, referring to FIG. 4, seal
body 22 includes three minimum thicknesses T1, T2 and T3 which are
all approximately equal to one another. Thickness T1 is formed
between the axial end of spigot-side portion 24B of stiffener 24
and the nearest exterior surface of seal body 22 near nose 36.
Thickness T2 is formed between the radially outward surface of
spigot-side portion 24B of stiffener 24 and spigot-side sealing
surface 26. Thickness T3 is between the radially inward surface of
central portion 24A of stiffener 24 and the nearest exterior
surface of seal body 22, adjacent main sealing lobe 30. In the
illustrated embodiment, thicknesses T1, T2 and T3 are all within
15-20% of one another, which promotes even distribution of forces
experienced by seal body 22 during use, including external forces
arising from seal deformation and deflection, as well as internal
forces exerted by stiffener 24 on seal body 22. For example, in the
illustrated embodiment (which is shown to scale as noted herein),
thickness T1 is about 0.1251 inches, thickness T2 is about 0.1493
inches, and thickness T3 is about 0.1468 inches for a maximum
variation of about 16%.
[0032] As noted above, seal body 22 and stiffener 24 are configured
to be assembled to one another by hand. The relatively low angle
.theta. formed between spigot end portion 24B and central portion
24A of stiffener 24, and the commensurately shaped portions of
stiffener pocket 32, facilitate this insertion. However, angle
.theta. is also large enough to inhibit removal or relative
movement of stiffener 24 from seal body 22 after installation,
thereby contributing to a "mechanical bond" between the two
components that arises from the relative geometry therebetween. In
addition, the relatively larger angle .gamma. between bell-end
portion 24C and central portion 24A also enhances this mechanical
bond, while still allowing manual assembly of stiffener 24 into
stiffener pocket 32.
[0033] This two-piece, interlocking design of seal assembly 20
provides consistent and positive positioning of stiffener 24 within
seal body 22, while also facilitating the complete and accurate
seating of stiffener 24 within stiffener pocket 32 such that
stiffener 24 completely occupies pocket 32. Moreover, stiffener 24
may be retained within seal body 22 during installation, and during
service of seal assembly 20, without the use of adhesives or other
chemical bonding. By contrast, predicate seal designs used for PVCO
piping typically use adhesive, chemical bonding or overmolded
designs, which are more expensive and complicated.
[0034] In addition, the two-piece design of seal assembly 20
facilities efficient manufacture with minimal waste, by allowing
seal body 22 and stiffener to be produced separately and in large
quantities and shipped to a customer or job site as separate
components. To the extent that a manufacturing defect may be found
either component, only that component needs to be replaced in order
to successfully assemble seal assembly 20. Separate manufacture of
seal body 22 as a monolithic and constant-density structure, as
noted above, also allows for high tolerance manufacturing at a
relatively low cost. Similarly, stiffener 24 may also be a
monolithic and constant-density structure which is also efficiently
produces to high tolerance standards.
[0035] Stiffener 24 also provides equalized distribution of forces
throughout seal body 22 during and after the assembly of second
pipe 16 to first pipe 12. During the insertion process, spigot end
18 of second pipe 16 is inserted into bell end 14 of first pipe 12
as shown in FIG. 6. As spigot end 18 advances into bell end 14, a
sloped surface 17 of spigot end 18 comes into initial contact with
main sealing lobe 30 as shown in FIG. 7. Main sealing lobe 30 is
then deflected progressively radially outwardly as it advances up
sloped surface 17, until it reaches a fully deformed and deflected
configuration shown in FIG. 8. In this configuration, the portion
of seal body 22 radially inward of stiffener 24 defines thickness
T4, while the portion of seal body 22 radially outward of stiffener
24 defines thickness T5. As illustrated, thicknesses T4 and T5 are
commensurate with one another, such as within about 15-25% of one
another. This facilitates even distribution of forces within seal
body 22 by stiffener 24, ensuring a fluid-tight interface between
main sealing lobe 30 and spigot end 18 of pipe 16, as well as at
the interfaces between the radial inward surfaces of groove 15 and
the radially outward surfaces 26, 28 and 29 of seal body 22. This,
in turn, ensures that pressurized fluid will not leak through any
potential leak path between pipes 12 and 16.
[0036] As noted above and shown in FIGS. 7 and 8, bell-side portion
24C of stiffener 24 abuts the inner surface of groove 15 between
bell-side sealing surfaces 28 and 29. This direct contact between
stiffener 24 and the sidewall of pipe 12 enhances the strength and
resilience of seal assembly 20. In particular, as spigot end 18 of
pipe 16 advances into bell end 14 of pipe 12 to deflect and deform
seal body 22, the abutting contact between the semi-rigid material
of stiffener 24 and the rigid material of pipe 12 allows stiffener
24 to transfer a portion of the insertion forces to the sidewall of
pipe 12. This reduces the overall stress upon seal body 22, thereby
reducing the potential for undesirable downward deflection of nose
36 into the insertion path (as also described in detail below).
[0037] The radially inward portion of seal body 22 includes main
sealing lobe 30, which extends continuously around its inner
periphery and, as noted herein, provides the primary sealing
surface for the interface of spigot end 18 of pipe 16 and seal
assembly 20. Main sealing lobe 30 extends radially inwardly of the
inner wall of bell end 14, as shown in FIG. 6. A spigot-end side of
seal lobe 30 is concave, while the bell-end side of lobe 30 is
generally planar. Lobe 30 is oriented to define a longitudinal lobe
axis AL forming angle .alpha. (FIG. 5) with respect to the axial
direction. In an exemplary embodiment, angle .alpha. is about 45
degrees, which facilitates smooth deformation and deflection of
seal lobe 30 as spigot end 18 of pipe 16 advances from initial
contact with lobe 30 (FIG. 7) to a fully installed configuration
(FIG. 8).
[0038] The spigot-side end of seal body 22, best shown in FIG. 4,
defines nose 36 forming the transition between sealing surface 26
and the adjacent radial inward surface leading toward lobe 30.
Along this radial inward surface of seal body 22 immediately
adjustment nose 36, concavity 38 forms an annular depression around
the inner periphery of seal body 22. Referring to FIG. 3, nose 36
and concavity 38 are positioned within groove 15 and radially
outside of the inner wall of bell end 14. In particular, the tip of
nose 36 defines distance D1 from the inner wall of bell end 14. In
one exemplary embodiment in which pipe assembly 10 defines a
nominal 8-inch diameter flow path, D1 is at least 0.05 inches,
thereby providing a level of protection against catching on pipe 16
during insertion as described below. In the illustrated, to-scale
embodiment, D1 is about 0.189 inches. More generally, a seal
assembly 20 made in accordance with the present disclosure (but
having a smaller or larger nominal size, as discussed herein) may
have a distance D1 that is at least 50% of each of thicknesses T1,
T2 and T3 or may be up to 20% greater than any of thicknesses T1,
T2 and T3, for example.
[0039] Other aspects of seal assembly 20 are similarly "tucked"
within groove 15. For example, distance D2 is defined between the
deepest part of concavity 38 and the inner wall of bell end 14, and
distance D3 is defined between the radially-inward-most point of
stiffener 24 (which is the axial end of spigot-end portion 24B) and
the inner wall of bell end 14. That is, the entirety of nose 36 and
stiffener 24, including their radially-inward-most portions, are
disposed within groove 15 and radially outside of the insertion
path of pipe 16. As illustrated in FIG. 3, distance D2 is less than
distance D1, and distance D3 is less than distance D3 as shown. In
the illustrated, to-scale embodiment, distance D2 is at least 0.171
inches and distance D3 is at least 0.110 inches.
[0040] In addition, the radial inward surface at the bell end-side
of seal body 22, including the surfaces on either side of the
trough formed by concavity 38, define angle .theta. with inner
surface of bell end 14 (which is substantially parallel to flow
axis A, shown in FIG. 1). In an exemplary embodiment, angle .theta.
defines a relatively low "entry angle" of contact between spigot
end 18 of pipe 16 and seal body 22 (FIG. 7). For example, angle
.theta. may be between 25 and 29 degrees, such as 27 degrees.
[0041] Distance D1 and angle .theta. cooperate to help to prevent
nose 36 from being deflected downwardly into the path of movement
for spigot end 18 of pipe 16 as it advances into contact with seal
assembly 20, as shown in FIGS. 7-9. To the extent that nose 36 is
deflected downwardly, (that is, radially inwardly) by the forces of
insertion of pipe 16, concavity 38 and the large nominal distance
D1 avoids or minimizes contact between nose 36 of seal body 22 with
pipe 16. This mitigates the potential for nose 36 to "catch" on the
outer surface of pipe 16 and mitigates the potential for seal
assembly 20 to then "roll" out of groove 15 during installation. In
predicate seal designs, this type of failure upon installation is a
particular risk in very cold weather installation where the
material of seal body 22 is less pliable, or in situations where
inadequate lubrication between the spigot end of the incoming pipe
and the seal. Similarly, concavity 38 and stiffener 24 are radially
outside of the insertion path of pipe 16 by distances D2 and D3
respectively as noted above. Both of these features are therefore
also protected from contact with pipe 16 during the insertion
process, thus mitigating the potential for any catching of seal
assembly 20 upon the outer surface of pipe 16.
[0042] Seal body 22 also includes locking fin 34, shown in FIGS.
3-9. Locking fin 34 is positioned at the bell-end side of seal body
22 and extends radially inwardly into the insertion path of spigot
end 18 (FIGS. 8 and 9) by amount substantially less than main
sealing lobe 30 in the undeformed configuration of seal assembly 20
(FIGS. 3-6). As shown, locking fin 34 includes a bell-end surface
with a radius larger than the adjacent spigot-end "point." At the
other side of this point, a spigot-end surface of locking fin 34
extends generally perpendicular to flow axis A (FIG. 1).
[0043] Turning to FIG. 8, the spigot-end "point" of locking fin 34
presents a small area of surface contact with the outer surface of
spigot end 18 of pipe 16 as pipe 16 is moving along the insertion
path shown FIGS. 7 and 8. However, as shown in FIG. 9, when pipe 16
is urged along a removal direction from bell end 14, locking fin 34
is designed to deflect downwardly (that is, radially inwardly) such
that its convex bell-end surface produces a larger surface area
contact with the exterior surface of spigot end 18. This increase
in surface area contact inhibits removal of pipe 16.
[0044] Locking fin 34 is axially spaced from main sealing lobe 30
such that, upon deflection and deformation of main sealing lobe 30
by contact with spigot end 18 of pipe 16 (FIG. 8), main sealing
lobe 30 avoids contact with locking fin 34. In addition, locking
fin provides a "backstop" for longitudinal deformation of main
sealing lobe 30. That is, main sealing lobe 30 can only be
longitudinally (that is, axially) deformed by a predetermined
amount before abutting the spigot-end surface of locking fin 34.
This predetermined amount of deformation of lobe 30 is set low
enough to protect main sealing lobe 30 from damage that might
otherwise occur if main sealing lobe 30 where allowed to
longitudinally deflect by a greater amount. This protects mail
sealing lobe 30 from adequate lubrication between pipe 16 and main
sealing lobe 30, for example, and from imperfections in the
exterior surface of pipe 16 that might "catch" the adjacent surface
of sealing lobe 30.
[0045] In the illustrative embodiment of FIGS. 1 and 2, pipes 12
and 16 have a nominal flow path diameter of about 8 inches, a size
commonly employed for transport and delivery of potable water. The
proportions of seal assembly 20, which are shown to scale
throughout the drawings, are appropriate to this 8 inch diameter.
However, it is contemplated that the nominal dimensions of seal
assembly 20, including all its features as described and shown
herein, may be scaled up or down to accommodate proportionally
larger or smaller pipe assemblies to which the seal assembly is
applied. Other nominal pipe diameters contemplated for use in
connection with a seal assembly having the features and proportions
of seal assembly 20 may be as little as 2 inches, 3 inches, 4
inches, 5 inches or 6 inches, or as large as 10 inches, 12 inches,
14 inches, 16 inches, 18 inches, 20 inches, or 24 inches, for
example.
[0046] In some cases, different manufactures may produce, and/or
differing manufacturing methods employed by the same manufacturer
may result in, slight diametric variations for a specified diameter
of pipe. For instance, a single manufacturer may utilize two
different manufacturing processes to produce pipe for the same
diameter. But given the differences in these manufacturing
processes, one or more of the diameters of the pipe (e.g., ID
and/or the OD) may deviate slightly from the specified diameter
during the manufacturing runs.
[0047] Turning to FIG. 10, different diameters of stiffener 24
(e.g., 24, 24', and 24'') are illustrated which can accommodate
variations in inner diameters (ID) of the bell end 14 of pipe 12
and/or the outer diameters (OD) of spigot end 18 of a second pipe
16. By using the correct size stiffener 24, a common seal assembly
20 can maintain a water-tight seal within groove 15 of bell end 14
by accounting for the variations in diameters of pipe 12 and/or
second pipe 16.
[0048] The variations in the ID and/or OD of the pipes can occur in
pipe 12 and/or second pipe 16. These variations can make it
difficult to utilize a common seal 20 to maintain a water tight
seal when the spigot end 18 of second pipe 18 is inserted into bell
end 14 of pipe 12. For example, pipe 12 may be specified as an 8
inch ID pipe, but due to variations in the manufacturing process,
the ID may deviate by 0.05 inches from specification (e.g., either
7.95 inches or 8.05 inches). Seal assembly 20 may be deigned to fit
into groove 15 of 8 inch ID pipe 12. As such, a water tight seal
between pipe 12 and second pipe 16 with too large a pipe 12 (e.g.,
8.05 inches ID) or too small of a pipe 12 (e.g., 7.95 inches ID)
may be difficult to achieve with seal assembly 20. These
manufacturing variations can also occur in the outer diameter of
spigot end 18 of second pipe 16. For example, spigot end 18 of
second pipe 16 may be specified as an 8 inch OD pipe, however, due
to the variations in the manufacturing processes, the OD of spigot
end 18 may also vary by 0.05 inches (e.g., either 7.95 inches or
8.05 inches), making it difficult for seal 20 to maintain a water
tight seal between pipe 12 and second pipe 16. In some other cases,
variations in both first pipe 12 and second pipe 16 can occur
simultaneously, making it even more difficult to use a common seal
20 to achieve a water tight seal between the two pipes.
[0049] In these cases, differing diameters of stiffener 24 can be
used with a common seal body 22 to compensate for the variations in
the ID of pipe 12 and/or the OD of second pipes 16. By using
differing diameters of stiffener 24 it is possible to account for
the variations in the diameters of the pipes and achieve sufficient
compression between the bell end 14 and spigot end 18 to create a
water tight seal. As discussed previously, seal assembly 20 is a
two piece interlocking design including a seal body 22 and
stiffener 24 where seal body 22 is made of a flexible material
(e.g., rubber). Due to the flexibility of the materials used in
seal body 22, seal assembly 20 is able to accommodate multiple
diameters of stiffener 24 within stiffener pocket 32. This allows
for the same (e.g., common) seal body 22 to be used with a variety
of diameters of stiffeners 24 (e.g., D1, D2, D3) to accommodate
differing IDs of pipe 12 and/or ODs of second pipe 16.
[0050] As discussed previously, stiffener 24 is sized to deform
seal body 22 such that thicknesses T5 and T4 are achieved once
spigot end 18 of second pipe 16 is inserted into bell end 14 of
pipe 12. Thicknesses T5 and T4 of seal body 22, under sufficient
compression, creates a water tight seal between pipe 12 and second
pipe 16. When the diameter of stiffener 24 is sized correctly to
the ID of pipe 12 and the OD of pipe 16 (e.g., D1), stiffener 24
provides the correct compression to deform seal body 22 to form a
water tight seal between the two pipes.
[0051] However, in the case where the ID of the bell end 14 is
larger than specification, too large of a gap can exist between
pipe 12 and second pipe 14 such that diameter D1 of stiffener 24
does not supply sufficient compression for seal body 22 to maintain
a water tight seal between the two pipes. In this case, a larger
stiffener 24' with a larger diameter D2 can be used to increase the
size of flexible seal 20. For example, the ceiling of stiffener 24
may increase by .DELTA.1, such that the overall diameter D1 of
stiffener 24 is increased to diameter D2 of stiffener 24'. In this
case, when stiffener 24' is inserted into stiffener pocket 32,
sufficient compression between bell end 14 and spigot end 18 can be
achieved to create a water tight seal due to the larger diameter D2
of stiffener 24' providing more compression against bell end
14.
[0052] However, in some cases, increasing the ceiling height of
stiffener 24 by .DELTA.1 (e.g., to diameter D1 of stiffener 24')
may not supply enough compression between pipe 12 and second pipe
14 (e.g., too large of a gap still exists between bell end 14 and
spigot end 18, even when using stiffener 24'). In this case, a
larger stiffener 24'' may be used where the height of the ceiling
of stiffener 24' is again increased by .DELTA.2 to a diameter D3.
In this case, stiffener 24'' is inserted into stiffener pocket 32
and sufficient compression of seal body 22 between bell end 14 and
spigot end 18 can now be achieved to create a water tight seal
between the two pipes. Although not illustrated, if sufficient
compression is still not achieved between the two pipes, larger
diameters of stiffener 24 can be inserted into stiffener pocket 32
until sufficient compression is achieved between the two pipes and
thus a watertight seal is formed. The process of inserting various
diameters of stiffener 24 into stiffener pocket 32 to account for
larger IDs of bell end 14 can also be used to compensate for
smaller IDs of diameters of bell end 14. In this case, smaller
diameters of stiffener 24 are inserted into stiffener pocket 32
until sufficient compression of seal body 22 is achieved to form a
water tight seal between the two pipes. Additionally, inserting
various diameters of stiffener 24 into stiffener pocket 32 can also
be used to compensate for either smaller or larger variations in
the OD of spigot end 18 to achieve sufficient compression of seal
body 22 to form a water tight seal between pipe 12 and second pipe
16. Furthermore, inserting various diameters of stiffener 24 into
stiffener pocket 32 can also be applied to scenarios where both the
OD of spigot end 16 and the ID of bell end 14 vary simultaneously
to attain sufficient compression of seal body 22 to form a water
tight seal between the two pipes.
[0053] The approach of inserting various diameters of stiffener 24
into stiffener pocket 32 to account for the manufacturing diametric
variations of pipe 12 and second pipe 16 can be performed at a
variety of times, including either before or at the time of
installation. In these cases, the timing when stiffener 24 is
inserted into stiffener pocket 32 be based on minimizing the impact
to the time required to install the pipes in the field.
[0054] For example, it may be known that a manufacturer of pipe 12
supplies pipe 12 with an ID of bell end 14 that is 0.05 cm greater
than specification. In this case, prior to shipping the pipe to the
field for installation, a stiffener 24 with a diameter sized to
accommodate the larger bell end 14 can be pre-installed into
stiffener pocket 32, such that when the on-site installation of
pipe 12 and second pipe 16 occurs, the manufacturing variation is
already accounted for (e.g., stiffener 24 is pre-installed). The
same process of accounting for known manufacturing variations via
pre-installation of a different diameter of stiffener 24 can also
be applied to smaller sizes of bell end 14 and/or larger and
smaller sizes of spigot end 14 when then diametric variations of
the pipes from are generally know. However, in some cases, the
variations in the IDs and ODs of the pipes may not be generally
know. In this case, the field technician may perform iterative
installation of various diameters of stiffener 24 to account for
the variations in the diameters of pipe 12 and/or second pipe 14.
This approach can also be used to correct for any incorrectly sized
stiffener 24 that has been installed prior to installation of the
pipe in the field.
Aspects
[0055] Aspect 1 is a seal assembly for a polymer pipe joint, the
seal assembly including an annular flexible seal body configured to
be installed about an inner periphery of the polymer pipe joint,
such that the seal body defines a flow path therethrough with a
flow axis, the seal body including a spigot-side sealing surface a
bell-side sealing surface angled with respect to the spigot-side
sealing surface, both the spigot-side sealing surface and the
bell-side sealing surface facing radially outwardly from the flow
axis; a main sealing lobe extending radially inwardly from the seal
body; and a stiffener pocket extending into the seal body from the
bell-side sealing surface; and an annular stiffener sized to be
received within and occupy the stiffener pocket.
[0056] Aspect 2 is the seal assembly of Aspect 1, wherein the seal
body further comprises a nose at a spigot-side end of the seal
body.
[0057] Aspect 3 is the seal assembly of Aspect 2, wherein a radial
inward surface extending away from the nose includes a
concavity.
[0058] Aspect 4 is the seal assembly of any of Aspect 1-3, wherein
the seal body further comprises a locking fin at a bell-end side of
the seal body, the locking fin extending radially inwardly from the
seal body by an amount less than the radial inward extend of the
main sealing lobe.
[0059] Aspect 5 is the seal assembly of Aspect 4, wherein the main
sealing lobe is sized to deflect and deform into contact with the
rest of the seal body but without contacting the locking fin.
[0060] Aspect 6 is the seal assembly of any of Aspects 1-5, wherein
the annular stiffener comprises: a central portion; a spigot-end
portion extending radially inwardly away from the central portion;
and a bell-end portion extending radially outward away from the
central portion.
[0061] Aspect 7 is the seal assembly of Aspect 6, wherein the
stiffener pocket has a shape and size commensurate with the shape
and size of the annular stiffener, such that the annular stiffener
occupies the entirety of the stiffener pocket.
[0062] Aspect 8 is the seal assembly of any of Aspects 1-7, wherein
the bell-side sealing surface comprises a first sealing surface and
a second sealing surface on opposite sides of the stiffener.
[0063] Aspect 9 is the seal assembly of any of Aspects 1-8, wherein
the seal body has a substantially constant durometer throughout its
cross-sectional area.
[0064] Aspect 10 is the seal assembly of any of Aspects 1-9,
wherein a durometer of the seal body is between 55 and 70 as
measured on the shore A scale.
[0065] Aspect 11 is the seal assembly of any of Aspects 1-10,
wherein the stiffener is mechanically bonded to the seal body,
without the use of adhesive or other chemical bonding.
[0066] Aspect 12 is the seal assembly of any of Aspects 1-11, in
combination with a first polymer pipe having a bell end including a
groove having the seal assembly received therein, the bell end
having a first radial extent upstream and downstream of the groove,
and the groove have a second radial extent larger than the first
radial extent, the seal body received within the groove and the
main sealing lobe extending radially inward of the first radial
extent.
[0067] Aspect 13 is the seal assembly of Aspect 12, wherein the
seal body further comprises a nose at a spigot-side terminus of the
seal body, the nose radially outside of the first radial
extent.
[0068] Aspect 14 is the seal assembly of Aspect 12 or Aspect 13,
further including a second polymer pipe having a spigot end
received within the bell end of the first polymer pipe, the spigot
end deforming and deflecting the main sealing lobe toward the seal
body.
[0069] Aspect 15 is the seal assembly of any of Aspects 12-14,
wherein the stiffener abuts an adjacent surface of the groove.
[0070] Aspect 16 is the seal assembly of any of Aspects 12-15,
wherein the bell-side sealing surface comprises a first sealing
surface and a second sealing surface on opposite sides of the
stiffener and engaged with the adjacent surface of the groove, such
that the stiffener pocket is sealed from the flow path.
[0071] Aspect 17 is a polymer pipe joint including a seal assembly
including an annular flexible seal body configured to be installed
about an inner periphery of the polymer pipe joint, such that the
seal body defines a flow path therethrough with a flow axis, the
seal body including a spigot-side sealing surface; a bell-side
sealing surface angled with respect to the spigot-side sealing
surface, both the spigot-side sealing surface and the bell-side
sealing surface facing radially outwardly from the flow axis; and a
main sealing lobe extending radially inwardly from the seal body;
and a nose at a spigot-side terminus of the seal body; and a first
polymer pipe having a bell end including a groove having the seal
assembly received therein, the bell end having a first radial
extent upstream and downstream of the groove, and the groove have a
second radial extent larger than the first radial extent, the seal
body received within the groove and the main sealing lobe extending
radially inward of the first radial extent, wherein the nose of the
seal body is radially outside of the first radial extent.
[0072] Aspect 18 is the polymer pipe joint of Aspect 17, wherein
the nose defines a distance from the first radial extent of the
first polymer pipe that is at least 50% of a minimum thickness of
the seal body.
[0073] Aspect 19 is a method of configuring a seal assembly for use
in sealing a bell of a first pipe and a spigot end of a second pipe
including: providing a sealing body assembly including a
spigot-side sealing surface, a bell-side sealing surface, a main
sealing lobe, and a stiffener pocket; providing two or more annular
stiffeners wherein each stiffener has a different size of an
annular diameter; selecting one of the one or more annular
stiffeners based on an annular diameter of the bell and an annular
diameter of the spigot; inserting the selected annular stiffener
into the stiffener pocket of the sealing body; and determining if a
seal between the bell-side sealing surface, the spigot-side sealing
surface, and the lobe is water tight after inserting the selected
annular stiffener into the stiffening pocket.
[0074] Aspect 20 is the method of Aspect 19, further including:
determining that the seal between the bell-side sealing surface,
the spigot-side sealing surface, and the lobe is not water tight
after inserting the selected annular stiffener; removing the first
annular stiffener from the stiffener pocket; selecting a second
annular stiffener from the one or more annular stiffeners based on
the annular diameter of the bell and the annular diameter of the
spigot; inserting the selected second annular stiffener into the
stiffener pocket of the sealing body; determining that the seal
between the bell-side sealing surface, the spigot-side sealing
surface, and the lobe is water tight after inserting the selected
second annular stiffener into the stiffening pocket.
[0075] While this invention has been described as having an
exemplary design, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *